[R] standardising a data matrix

[Douglas Bates]

Paulo Justiniano Ribeiro Jr <p.ribeiro at lancaster.ac.uk> writes:

> What about apply:

> apply(onorm, 2, function(x){(x - mean(x))/sqrt(var(x))})

I think if the data were read with read.table they would be in the
form of a data frame and you would need to use lapply, not apply.  It
would look like

  lapply(onorm, function(x){(x - mean(x))/sqrt(var(x))})

I have a vague recollection of a function in the base library that
does centering and scaling but I can't remember what it is called.  It
is certainly easy enough to create an anonymous function as you did
although that function will encounter problems with missing data.


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